1. Field of the Invention
This invention is directed to a load-leveling apparatus for utilization in large household appliances, such as dishwashers, where the appliance is required to be substantially level for proper operation. More specifically, it is directed to a load-leveling apparatus which will allow for horizontal movement of the load without placing significant forces on the vertical adjustment mechanism.
2. Description of the Prior Art
Household appliances, such as dishwashers, refrigerators and clothes washers and dryers, are required to be substantially level during operation. For example, the gearing of the revolving arm of a dishwasher is manufactured to small tolerances allowing for minimal friction between moving parts. A dishwasher in an unlevel position produces undesired forces on the arm; thereby, increasing friction between the arm and its receiving mechanism. Such friction eventually causes heat and increased wear on the parts creating a wobbling movement and probably structural failure or freeze-up. Also, water spillage may occur if the dishwasher tank is not level.
Conventional methods of leveling such appliances utilize a bolt-type arrangement whereby the bolt is mounted vertically on a side or corner of the appliance so that an end of the bolt rests on the floor and is rotated to lift or lower the appliance to the level position. The bolt typically has an increased surface area on the end of the bolt contacting the floor. The disadvantage of such a construction is apparent when the appliance is moved horizontally to another location. The bolt of the conventional device receives a large portion of the appliance's weight. In actuality, if leveling devices are placed at the four corners of the appliance, the weight is distributed only to those four bolts. Therefore, when moved horizontally, the resisting frictional force is distributed to the bolts. Lateral forces of such magnitude can cause stress fractures in the bolt and very high torsional loads at the attachment point, causing them to destruct.
Another disadvantage of conventional methods is that the area of the bolt contacting the floor is small; therefore, the weight per square inch is large. Such weight over a small area can cause damage to a soft floor, such as linoleum, leaving a permanent indentation or depression.
Furthermore, the conventional methods will likely cause damage to the floor when the leveling apparatus is adjusted. The bolt, as it is turned, remains in contact with the floor. This turning motion creates circular scratch marks on the floor.
There is, therefore, a long recognized need for an improved load-leveling apparatus which will not be affected by lateral forces as the load is moved. Accordingly, it is an object of the invention to provide an apparatus whereby lateral forces from horizontal movement of the appliance are dissipated and only minimal lateral forces are transmitted to the vertical support mechanism. Another object is to provide a larger surface area for contact with the floor facilitating ease of horizontal movement.
Another object is to provide an apparatus whereby the load bearing capability is not diminished by increased extension of the bolt.
Another object is to provide an apparatus that may be used as both a leveler and as a height adjustment mechanism.
Another object is to provide a leveling apparatus that may be adjusted after the appliance is positioned in place.
Another object is to provide an apparatus whereby the entire load is supported by the axial strength of the vertical support mechanism.
Another object is to provide an apparatus whereby the portion contacting the floor has generally a horizontal attitude allowing for a more efficient horizontal movement of the dishwasher.
Another object is to provide an apparatus in which no height is added to the appliance when the vertical support means is fully retracted.
Another object is to provide an apparatus whereby the member contacting the floor does not rotate.
Another object is to provide an apparatus whereby adjustments may be made on the apparatus while bearing the full weight of the load.
Another object is to provide an apparatus whereby no horizontal motion is imputed to the load during adjustment of the apparatus.